Motor fuel



Patented Apr. 23, 1940 MOTOR FUEL Melvin A. Dietrich, Claymont, Del., asaignor to E. 1. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing.

Application August 12, 1938,

Serial No. 224,493

18 Claims.

This invention relates to motor fuels and particularly to motor fuels containing addition agents for reducing formation of gummy deposits in the motor, and to the removal of preformed gummy deposits from motors.

It is well known that deposits of gummy materials are formed more or less rapidly on the parts of internal combustion engines in use. Such gummy deposits are decidedly objectionable and make necessary frequent and expensive cleaning of the engine.

It is an object of the present invention to provide an improved motor fuel which will have a substantially reduced tendency to form adherent deposits of gums or carbonaceous materials on the various parts of the engine with which it comes in contact. Another object is to provide an improved. motor fuel which will soften, loosen and may even remove adherent deposits of gum or carbonaceous materials from the surface of the parts of the engine with which it comes in contact. A further object is to provide an improved motor fuel as above defined, and which will also lubricate the moving parts of the engine withwhich it comes in contact. A still further object is to provide a method for removing deposits of gummy and carbonaceous materials from the parts of an internal combustion engine. Other objects are to provide new compositions of a matter and to advance the art. Still other objects will appear hereinafter.

The above and other objects may be accom-' wherein R and R1 preferably represent hydrocarbon radicals such as alkyl, cycloalkyl, aralkyl, aryl and unsaturated aliphatic hydrocarbon radicals, and R2 preferably represents hydrogen or 50 a hydrocarbon radical such as alkyl, cycloalkyl,

aralkyl, aryl and unsaturated aliphatic hydrocarbon radicals. While compounds, which, exceptfor the SOi-N, consists of carbon and hydrogen, are preferred, compounds in which either one or u all of R, R1 and R: carry substitu'ents, such as halogens and nitro groups, are included so lon as they have the other necessary properties.

The preferred compounds are liquids at normal atmospheric temperatures and have melting points below 30 C. Also the N-alkyl substituted 5 aryl sulfonamides in which the total number ofcarbon atoms in the alkyl group or groups is at least 5 appear to be the most eflicient for my purpose and hence are preferred.

The sulfonamides of my invention are miscible with gasoline and similar motor fuels. When incorporated in the gasoline, they reduce the tendency of the motor fuel to deposit solid, adherent, gummy and resinous materials on the parts of the engine. Different motor fuels tend to deposit different amounts of gummy materials which may be determined by the usual gum test. In general, suflicient of the sulfonamide will be employed to dissolve, or at least render fluid, any amount of gummy material which the fuel may tend to deposit. Under such circumstances, my compounds will ordinarily completely prevent the deposition of gummy materials by such motor fuel. Usually, an excess of compound, over that u necessary to prevent deposition of gummy materials, is employed, and under such circumstances my compounds will tend to remove preformed deposits on the engine.

The amount of sulfonamide to be incorporated an in the motor fuel may be varied over a wide range, but ordinarily from about 0.01 to about 5.0% will be sufficient. Usually, about 0.5% will be employed. The motor fuel containing the sulfonamide will be used-in the engine in the usual manner. Continuous use ofsuch fuel has the advantage not only of preventing the accumulation of additional deposits, but also of removing gum deposits already present. The amount to be used will be determined to some extent by 0 III the quantity of gum which the motor fuel tends to deposit, and by the quantity of gum which it is desired to remove. Under certain conditions where the motor is in badly gummed condition, it may be desirable to inJect the liquid sulfonamide directly into the motor either with or without a small amount of carrier solvent and to allow the motor to stand for a short period of time to permit the sulfonamide to loosen such deposits prior to operation of the motor. Furthermore, since 50 the sulfonamides of my invention are viscous materials quite stable thermally and have relatively low ccefiicients of friction, they serve to lubricate the moving parts of the engine with which they come in contact, such as the valves, piston rings ,3

and cylinder walls which are frequently exposed to the hottest temperatures.

The compounds of my invention may be used in a wide variety of engines where gumming troubles occur. These include engines of the spark ignition type, such as the present day automobile engines, and engines of the auto-ignition type, such as the Diesel engine. They may be used in motor fuels of the gasoline, kerosene or gas oil range, and even in synthetic fuels such as polymerized isobutylene, dlisopropyl ether, various low boiling alcohols, benzene, toluene and mixtures of two or more thereof. They may be used as the sole addition agents to the motor fuels, or they may be used in conjunction with other relatively low boiling solvents such as decahydronaphthalene, dichloroethane and the like, to facilitate solution. They may likewise be used in conjunction with organo-metallic compounds, such as tetraethyl lead.

Examples of suitable compounds of my invention, together with their boiling points, are as follows:

The solvent action of these materials for gum was determined by measuring the tolerance of a butanol solution of kauri gum to dilution with the compounds. This is a type of test which is frequently used as an index of gum solvent power. The kauri-butanol solution was prepared by dissolving 80 grams of a good grade of kauri gum in 400 grams of butyl alcohol, allowing the solution to stand until any extraneous matter had settled and decanting the clear layer for use. To determine the gum solvent power of the compounds under test, 1 cc. of the kauributanol solution was placed in a test tube and the compound was slowly dropped in from a burette with stirring until a haze appeared. In all cases no haze developed after the addition of as much as 4 cc. of the compounds of my invention. This indicates a very high degree of solubility of the gum in these compounds. Accordingly, when I use the term high solvent power for kauri gum, I mean that the compound possesses a degree of solvency for kauri gum such that no haziness developes when 1 cc. of a 20% solution of kauri gum in butanol is diluted with 4 cc. of the compound.

When other types of compounds which havebeen proposed for this purpose and which are liquid at ordinary temperatures were tested in the same manner, a lower, degree of solubility for the gum was obtained. Thus, when a representative high boiling ester, butyl stearate, was tested in the same manner, only 1.7 cc. could be added to the kauri gum solution before a haze appeared therein.

It is also desirable that compounds for this purpose have a low vapor pressure so that they may be retained on the walls of the engine for a reasonable length of time. My compounds have this desirable property, as will be shown Time for Nature of Compound evaeggiron deposits N-di-butyl p-toluene sulionemide. 24 No deposits. N-di-isobutyl p-toiuene sulfonsmide 16 No deposits. N-(i'irgthylhcxyl) p-tolucnc suiiona- 20 No deposits.

in e. N-diacthylhexyi) p-toiucnc suliona- 45 No deposits.

in e. N-but lxyienc suifonamide No deposits. N-cy oliexyl cyclohexane sulionamide. 32 No deposits. Butyi stoarate i6 Bixwnish resi- From. these tests, it will be apparent that my compounds had a. low vapor pressure and left no deposits on the block. On the other hand, a. representative compound of the prior art, butyl stearate, had a higher vapor pressure and left a brownish deposit.

Other representative compounds of the prior art are also objectionable in this respect, as they tend to deposit black and tarry residues under the conditions of the above test. For comparison,

the following table shows the results of tests on somewhat similar compounds of the prior art of comparable boiling points:

Time for N t f B we raa ure 0 0i m Compound t on deposits point seconds C. N-dibutyl amide of coconut oil 10 B to w n is h 335-340 acids. residue. N-dimethyl amide oi coconut 9 Black de- 315-317 oil acids. posit.

It thus appears that my compounds have a low vapor pressure; that is, they require more than 15 seconds to evaporate when one drop thereof is placed on a plate heated to 300 C. The compounds of the prior art have a relatively higher vapor pressure.

In order to illustrate the effect of a representative member of my compounds on the gum deposited by a representative gasoline, 100 cc. of gasoline was placed in a weighed dish and evaporated on a. steam bath, followed by heating for 1.5 hours at 175 C. in a hot air blast. The results are as follows:

Mg. gum

per 100 cc.

gasoline Gasoline alone 446 Gasoline plus 0.50% N-di-(Z-ethyl-hexyl) p-toluene sulfonamide 360 The weights in the above test were corrected for the amount of sulfonamide that was added and for evaporation loss of the sulfonamide. The gum deposited by the gasoline alone was hard and resinous at 175 C., and spread over the sides of the dish as a tenacious deposit. That from the treated gasoline, gasoline containing a. compound of my invention, was fluid at the temperature of test and collected as a liquid in the bottom of the dish.

other compounds of my invention which are suitable for use in motor fuels and the like are as follows: 1

N-octyl xylene sulionamlde,

N-oleyl i-meth l-cycloliexane sulfonamlde Noctyl 2,4,0-tr methyl benzene sulfonamlde N-dlisoamvll p-toluene sulfonamlde N-dlbutyl exodecylsulfonamlde N-dloctyl cyclohcxane sulfonamlde N-(Z-ethylhexyl) cyclohexsne sullonamlde N-amyl toluene sulfonemide N-grop -p-bromo-ben1.cne sulionamlde N uty -p bromo-benzene sulfonamide N-lsobutg-m-nltro-benzene sullonamide N-butyl- -amyl-p-chloro-m-toluene sulfonamlde N-dlamyl-m-chloro-p-tolucne sullonamlde N-ethyl-N- ropyl+ebloro-3-nitro-benzenc sullonamide N-dllsoamy -m-nitro-p-tolueue sulfonamide The sulfonamides of my invention may be obtained in the known manner by the reaction of aryl or alkyl sulfonyl chlorides with aryl or alkyl amines of suitable chain length. Obviously, by variation of the number of carbon, atoms in either or both reactants, a product having the desired boiling point may be obtained. Sulfonamides, derived by the reaction of parailln wax sulfonyl chlorides and alkyl or aryl amines, may be employed in accordance with my invention, but do not appear to be as satisfactory as the alkyl substituted aryl sulfonamides. Also disulfonamides derived from compounds such as 1,5-naphthalene disulfonyl chloride may be used. Further, mixtures of sulfonamides in which the mixture has the properties hereinbefore specified, especially with respect to melting point, may be employed.

It will thus be apparent that my invention permits the production of a motor fuel which will substantially reduce and prevent the formation of gum deposits in a motor under operating conditions, which motor fuel at the same time will serve to lubricate the moving parts normally found in the upper part of the engine, thereby reducing wear and permitting longer periods of operation between overhauls. tion provides for the removal of preformed gummy deposits in an engine by means of the motor fuel employed therein or, in extreme cases, by my compounds per se, or a concentrated solution in a carrier solvent.

While I have disclosedthe preferred embodiments of my invention and the preferred modes of carrying the same into effect, it will be readily apparent to those skilled in the art that many variations and modifications may be made there- 'in, particularly in the compounds employed, the

motor fuel and in the proportions, without departing from the spirit of my invention. Accordingly, the scope of my invention is to be limited solely by the appended claims construed as broadly as ispermissible in view of the prior art.

I claim:

1. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which .normally tends to form gummy materials, having incorporated therein a minor proportion of an N- substituted organic-sulfonamide which, except for the SOs-N, consists of carbon and hydrogen and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power -for kauri gum and which sulfonamide is compatible with the motor fuel.

2. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which normally tends to form gummy materials, having incorporated therein a minor proportion of an N- alkyl organic-suifonamide which, except for the SOa-N, consists of carbon and hydrogen and which sulfonamide has a boiling point of at least Also, my inven-- mally tends to form gummy materials, having incorporated therein a minor proportion of an N- alkyl aryl-sulfonamide which has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum and which sulfonamide is compatible with the motor fuel.

4. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which normally tends to form gummy materials, having incorporated therein a minor proportion of an N- alkyl-sulfonamide in which the alkyl radicals contain a total of at least 5 carbon atoms and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum and which sulfonamide is compatible with the motor fuel.

5. A motor fuel, a major proportion of which I corporated'therein a minor proportion of N-di- (2-ethylhexyl) p-toluene sulfonamide.

'7. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which nor-- mally tends to form gummy materials, having incorporated therein a minor proportion of N- cyclohexyl cyclohexane sulfonamide.

8. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which normally tends to form gummy materials, having incorporated therein a minor proportion of N- dibutyl hexadecyl sulfonamide.

9. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-substituted organic-sulfonamide which, except for the SOs-N, consists of carbon and hydrogen and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum.

10. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-alkyl organic-sulfonamide which, except for the SO2-N, consists of carbon and hydrogen and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum.

11. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-alkyl aryl-sulfonamide which, except for the SOs-N, consists of carbon and hydrogen and which sulfonamlde has a boiling point'of at least 800 0., a melting point below 75 C. and a high solvent power for kauri gum.

12. In the method of removing deposits .of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-alkyl aryl-sulfonamide in which the alkyl radicals contain a total of at least 5 carbon atoms and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum.

13. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-dialkyl aryl-sulfonamide in which the alkyl radicals contain a total of at least 5 carbon atoms and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum.

14. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with N-di(2-ethylhexyl)p-toluene sulfonamide.

15. In the method of removing deposits of gummy and carbonaceous materials from an intemal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with N-cyclohexyl cyclohexane sulfonamide.

16. In the method of removing deposits of gummy and carbonaceous materials from an inaromu V ternal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with N-hexadecyl sulfonamide.

17. A motor fuel, a major proportion of which consists of liquid hydrocarbons and which normally tends to form gummy materials, having incorporated therein a minor proportion of an N- substituted organic-sulfonamide of the group consisting of sulfonamides which, except for the SOs-N, consist of carbon and hydrogen, sulfonamides which, except for a halogen and the Boa-N, consist of carbon and hydrogen and suli'onamides which, except for a nitro group and the SOs-N, consist of carbon and hydrogen, and which sulfonamide has a boiling point of at least 300 C., a melting point below 75 C. and a high solvent power for kauri gum and which sulfonamide is compatible with the motor fuel.

18. In the method of removing deposits of gummy and carbonaceous materials from an internal combustion engine employing motor fuels which consist mainly of liquid hydrocarbons, the step which comprises contacting the deposits with an N-substituted organic-sulfonamide of the group consisting of sulfonamides which, except for the SOs-N, consist of carbon and hydrogen,

sulfonamldes which, except for a halogen and the SOs-N, consist of-carbon and hydrogen and sulfonamides which, except for a nitro group and the SOs-N, consist of carbon and hydrogen, and which sulfonamide has a boiling point of at least 300 C., a melting point below C. and a high solvent power for kauri gum and which sulfonamide is compatible with the motor fuel.

MELVIN' A. DIE'IRICH. 

